docs: def npoints_between(lon1, lat1, depth1, lon2, lat2, depth2, npoints):
      """
      Find a list of specified number of points between two given ones that are
      equally spaced along the great circle arc connecting given points.
  
      :param float lon1, lat1, depth1:
          Coordinates of a point to start from. The first point in a resulting
          list has these coordinates.
      :param float lon2, lat2, depth2:
          Coordinates of a point to finish at. The last point in a resulting
          list has these coordinates.
      :param npoints:
          Integer number of points to return. First and last points count,
          so if there have to be two intervals, ``npoints`` should be 3.
      :returns:
          Tuple of three 1d numpy arrays: longitudes, latitudes and depths
          of resulting points respectively.
  
      Finds distance between two reference points and calls
      :func:`npoints_towards`.
      """
      hdist = geodetic_distance(lon1, lat1, lon2, lat2)
      vdist = depth2 - depth1
      rlons, rlats, rdepths = npoints_towards(
          lon1, lat1, depth1, azimuth(lon1, lat1, lon2, lat2),
          hdist, vdist, npoints
      )
      # the last point should be left intact
      rlons[-1] = lon2
      rlats[-1] = lat2
      rdepths[-1] = depth2
      return rlons, rlats, rdepths